VULNERABILITY INTELLIGENCE

CVE-2026-27459

CVSS score9.8 CRITICAL

EPSS probability0.73%

CISA KEVNot currently listed

Published2026-03-18

Last modified2026-09-10

Description

pyOpenSSL is a Python wrapper around the OpenSSL library. Starting in version 22.0.0 and prior to version 26.0.0, if a user provided callback to `set_cookie_generate_callback` returned a cookie value greater than 256 bytes, pyOpenSSL would overflow an OpenSSL provided buffer. Starting in version 26.0.0, cookie values that are too long are now rejected.